My issue is that the gap on all my windows is too small to mount my contact sensors in a way that will detect an opening from the bottom and top of the window.
So I bought these magnets from Amazon.
Magnets: 1/8 in x 1/16 in (50) 10003 https://www.amazon.com/dp/B00TGDMPDW/ref=cm_sw_r_cp_api_oBTHxbCNZ0A2J
Fixed them up like this.
Works great. Right now just stuck there with double sided tape. I am going to get some plasti dip and make them white with a more clean stick surface.
Now if you open from the top or bottom the sensor catches it.